Electrical power storage and delivery using magnetic levitation technology

ABSTRACT

One or more magnetic levitation vehicles are provided to transport a storage mass over a magnetic levitation guideway extending between an elevated upper end and a lower end at a lower elevation, and including a plurality of magnetic propulsion windings. Movement of a magnetic levitation vehicle with the storage mass along the magnetic levitation guideway from the elevated upper end to the lower end generates electrical energy through the propulsion windings of the magnetic levitation guideway. The magnetic levitation vehicle with a storage mass can be propelled from the lower end to the upper end of the magnetic levitation guideway, where the storage mass is unloaded to store gravitational potential energy. The magnetic levitation vehicle and storage mass can then be moved to the lower end of the magnetic levitation guideway to convert the stored gravitational potential energy to electrical power. The magnetic levitation guideway can be an inclined guideway or a vertically oriented guideway, can be a surface guideway, can be disposed in a sub-surface tunnel, or can be a combination of a surface guideway and a sub-surface tunnel.

This is a National Phase Application in the United States of America ofInternational Application PCT/US02/08768 filed 22 Mar., 2002, whichclaims priority from U.S. provisional application Ser. No. 60/279,142filed Mar. 26, 2001.

BACKGROUND OF THE INVENTION

This invention relates generally to a magnetic levitation vehiclesystem, and more particularly concerns a system for electrical powerstorage and delivery by a maglev vehicle such as a maglev train.

The demand for electric power from regional power grids is not constant,but varies substantially with time. Typically, power demand is lowduring the night time, increasing substantially during the day, asillustrated in FIG. 1. Much of the time, electrical grids experience twodistinct peak demand periods, the first in the morning and the second inthe afternoon. Power demand also varies considerably with the day of theweek, being higher during the Monday to Friday period, and lower onweekends. It also varies considerably with the seasons, with the summerdemand usually being substantially higher than during the rest of theyear.

It would be expensive, and technically difficult to have coal andnuclear power plants go up and down in power output to meet thefluctuating load demand. Instead, peaking power is generally suppliedeither from combustion fired low capital cost units (e.g., turbines orcombined cycle plants), or from energy storage units that take insurplus power from baseload plants during low power demand periods andreturn it to the grid during high demand periods. Presently, spinningreserve is provided by keeping expensive generator units hot and readyto generate large blocks of power in a very short notice.

FIG. 2 shows the current leading conventional options for peaking power.Of the present energy storage options, only pumped hydroelectric power(pumped hydro) is used to any extent. Batteries, flywheels, andsuperconducting energy storage (SMES) are too expensive to be practical.While pumped hydro can be practical in terms of cost, its environmentaland siting problems severely constrain its usefulness.

Existing technologies for electrical power storage, such as batteries,flywheels, and superconducting energy storage (SMES) are generally tooexpensive and difficult, or too limited in siting, such as pumped hydro.To be useful, the great majority of peak power demand is supplied byfossil fueled peaking power plants—e.g., gas turbine—or by purchase fromdistant power grids. Such power generating units generally use oil ornatural gas fuel. In fact, many units are designed so that they can burneither fuel, and switch back or forth depending on which is cheaper at agiven point in time. The long term outlook for oil and natural gasprices is a continual increase, which will cause further hikes in thecost of peak power.

The cost of supplying peaking power can be high. For California inAugust of 2000, peak prices of about $500 per MWH (50 cents per KWH)were paid during this period, prior to a state cap of about $250 per MWH(25 cents per KWH) imposed on Aug. 17, 2000. The peak cost is a factorof 10 greater than the minimum cost, which would apply during low demandperiods, e.g., night time. This large differential, and the high cost ofpeak power, provides a major opportunity for a low cost energy storagesystem. By buying low cost power at night storing it, and delivering itduring the day at peak power rates, a low cost storage system could bemore efficient and economical. An energy storage system that could storelarge amounts of electric power for a few cents per KWH would enablecost savings of hundreds of billions of dollars annually over the world.

The cost of wind generation of electricity was once seen as prohibitive,but is now becoming more competitive. Wind generation of electricityproduces no emissions, is renewable, and is one of the cleanest sourcesof electricity. The same is true for solar generation of electricity.However, until an adequate electrical power storage technology can bedeveloped, utilities can not rely on wind or solar generated electricityfor peaking power requirements. While wind and solar generation ofelectricity account for a small fraction of the nation's electricity,and can be intermittent and unpredictable, with an adequate electricalpower storage technology, wind and solar energy could be used togenerate electrical power that could be stored for introduction into thepower grid as needed. It thus would be desirable to provide a new energystorage technology that can provide a low cost, near term method ofstoring large amounts of electrical energy and delivering it rapidly andin the amounts needed to the grid. The present invention addresses theseand other needs.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the present invention provides for asystem and method for generation of electrical energy, in which at leastone magnetic levitation vehicle is provided to transport a storage mass,and a magnetic levitation guideway is provided for the at least onemagnetic levitation vehicle. The magnetic levitation guideway extendsbetween an elevated upper end and a lower end at a lower elevation, andincludes a plurality of magnetic propulsion windings for propulsion ofthe at least one magnetic levitation vehicle. Movement of the at leastone magnetic levitation vehicle along the magnetic levitation guidewayfrom the elevated upper end of the magnetic levitation guideway to thelower end of the magnetic levitation guideway generates electricalenergy through the propulsion windings of the magnetic levitationguideway.

The present invention also provides for a system and method for storageand generation of electrical energy, in which at least one magneticlevitation vehicle is provided, and a magnetic levitation guideway isprovided for the at least one magnetic levitation vehicle. The magneticlevitation guideway extends between an elevated upper end and a lowerend at a lower elevation, and includes a plurality of magneticpropulsion windings for propulsion of the at least one magneticlevitation vehicle. At least one storage mass is loaded on the at leastone magnetic levitation vehicle at the lower end of the magneticlevitation guideway, and the at least one magnetic levitation vehicle ispropelled with the at least one storage mass from the lower end of themagnetic levitation guideway to the upper end of the magnetic levitationguideway. The at least one storage mass is unloaded from the at leastone magnetic levitation vehicle at the upper end of the magneticlevitation guideway to store gravitational potential energy. The atleast one magnetic levitation vehicle can then be moved as desired fromthe elevated upper end of the magnetic levitation guideway to the lowerend of the magnetic levitation guideway to convert the storedgravitational potential energy to electrical power through thepropulsion windings of the magnetic levitation guideway.

In one currently preferred embodiment, the magnetic levitation guidewayis an inclined guideway, and in another presently preferred embodiment,the magnetic levitation guideway is a vertically oriented guideway. Themagnetic levitation guideway can be a surface guideway, can be disposedin a sub-surface tunnel, or can be a combination of a surface guidewayand a sub-surface tunnel.

The system of the invention for electrical power storage and delivery isvery flexible and can rapidly alter its power level by changing the rateat which the storage masses are moved up or down the guideway. Forexample, the power level for the system of the invention for electricalpower storage and delivery could go from zero to 100% of fullcapability, or from 100% to zero, in less than one minute. The storagemasses can be rapidly moved onto a maglev vehicle or off the vehicle forstorage using an overhead trolley-wheel or surface rollway system. Peakpower capabilities of about 1000 MW(e) can be generated using the systemof the invention for electrical power storage and delivery. Because ofits rapid response capability, in addition to providing peak power, thesystem of the invention for electrical power storage and delivery couldalso be used for low cost spinning reserve.

The much steeper grades for the system of the invention for electricalpower storage and delivery (45 degrees or more, versus a maximum ofabout 10 degrees for passenger/freight transport), together with theconsiderably heavier vehicles (about 100 tons vs a maximum of about 50tons for freight transport) necessitates much greater propulsion forces,i.e., a factor of 10 or more. The above requirements, coupled with theheavier loads and much shorter vehicles (about 6 meters for the systemof the invention for electrical power storage and delivery, vs about 30meters for passenger/freight vehicles) are accommodated by a magnetconfiguration which maximizes propulsion force relative to power (I²R)losses in the propulsive winding. The propulsion winding/vehiclecombination can operate with a pure sine wave 60 Hertz input in themotor mode, and can deliver a pure sine wave 60 Hertz output in thegenerator mode. Alternatively, conventional AC/DC power conversionequipment can be used to have the propulsion winding vehicle systemoperate at a different frequency than the 60 Hertz external power gridand still allow it to receive and deliver power to the grid as required.

In addition to its economic benefits, the system of the invention forelectrical power storage and delivery is very attractive in terms of theenvironment. It has minimal impact on the environment, and can be sitedvirtually anywhere. Moreover, because it has very low cost, and canstore large amounts of energy, it is a very attractive partner for solarand/or wind power, since it can deliver reliable power to the grid whenthe solar or wind plants are not operating. The system of the inventionfor electrical power storage and delivery would eliminate the need forexpensive, fossil fuel burning power plants that normally would benecessary to supply backup power to the grid whenever the sunlight orwind generated power could not meet demand—i.e., during the night timeor cloudy days, or when the wind stopped.

Most facilities for the system of the invention for electrical powerstorage and delivery would be sited in remote areas and would not impactthe environment. The total land use for a 2000 MWH facility, including adual 3 km long guideway, is only about 20 acres. The small landfootprint and absence of environmental problems, together with its lowstorage cost, make the system of the invention for electrical powerstorage and delivery very attractive for peaking power and spinningreserve applications, in substitution for conventional peaking powerplants that burn fossil fuels and produce pollution. The system iscompletely non-polluting and environmentally benign. At the design speedof 130 mph, the vehicles would be virtually silent, with aerodynamicnoise below ambient levels, should make it possible to obtain permitsand site approval very quickly and easily. Furthermore, since the maglevguideway would not carry passengers, safety certification would beconsiderably easier.

The system of the invention for electrical power storage and delivery isvery attractive for near term peaking power needs. It is even moreattractive for low cost energy storage used in conjunction with solarand wind power generation. Combined with the system of the invention forelectrical power storage and delivery, however, solar and wind sourcescan deliver steady, reliable power that meets variations in load demand.The system of the invention for electrical power storage and deliverywould fit in very well with a natural gas fired power economy, allowingthe natural gas plants to operate close to full time during the year,with low cost energy storage provided by the system of the inventionproviding peak power.

These and other aspects and advantages of the invention will becomeapparent from the following detailed description and the accompanyingdrawings, which illustrate by way of example the features of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart illustrating the typical power peaking periods onelectrical grids.

FIG. 2 is a chart illustrating the principal options for providingpeaking power requirements.

FIG. 3A is a schematic diagram of the energy storage mode of the systemof the invention for electrical power storage and delivery.

FIG. 3B is a schematic diagram of the power generation mode of thesystem of the invention for electrical power storage and delivery.

FIG. 4 is a schematic diagram illustrating the amount of energy that canbe stored by raising a 100 ton mass to a 2000 meter change in elevation,according to the system of the invention for electrical power storageand delivery.

FIG. 5 is an operational flowsheet for the system of the invention forelectrical power storage and delivery.

FIGS. 6A–6D illustrate the types of locations for a system forelectrical power storage and delivery according to the presentinvention.

FIG. 7A shows an end view of a guideway beam with a typical propulsionloop/vehicle magnet configuration for a passenger/freight vehicle.

FIG. 7B shows a side view of a guideway beam with a typical propulsionloop/vehicle magnet configuration for a passenger/freight vehicle.

FIG. 8A shows an end view of a guideway beam with a typical propulsionloop/vehicle magnet configuration for an energy storage vehicleaccording to the system of the invention for electrical power storageand delivery.

FIG. 8B shows a side view of a guideway beam with a typical propulsionloop/vehicle magnet configuration for an energy storage vehicleaccording to the system of the invention for electrical power storageand delivery.

FIG. 9A shows an end view of an energy storage vehicle on a guidewaybeam with a storage mass, according to the system of the invention forelectrical power storage and delivery.

FIG. 9B shows an end view of an energy storage vehicle on a guidewaybeam with an energy storage vehicle without a storage mass, according tothe system of the invention for electrical power storage and delivery.

FIG. 10 illustrates the magnetic functions of a narrow beam guidewayproviding lift to an energy storage vehicle according to the system ofthe invention for electrical power storage and delivery.

FIG. 11 shows the layout of the energy storage facility according to thesystem of the invention for electrical power storage and delivery.

FIG. 12 is a chart showing the effect of vehicle speed on theperformance of the system of the invention for electrical power storageand delivery.

FIG. 13 is a chart showing the position and speed of the vehicle in thebaseline power storage cycle according to the system of the inventionfor electrical power storage and delivery.

FIG. 14 is a chart illustrating the number of round trips per hourachievable for an energy storage vehicle as a function of vehicle speedand guideway angle.

FIG. 15 illustrates the magnetic geometry and calculation of themagnetic propulsive forces and power for an energy storage vehicleaccording to the invention.

FIG. 16 is an illustration of vector addition of magnetic propulsion andmagnetic lift forces for an energy storage vehicle according to theinvention.

FIG. 17 is a graph illustrating the values of By as a function of z andy₀ positions for an energy storage vehicle propulsion system.

FIG. 18 is a graph illustrating guideway propulsion current and themagnetic field from energy storage vehicle loops as a function of time.

FIG. 19 is a schematic diagram illustrating the geometry of three phasepropulsive windings for the system of the invention for electrical powerstorage and delivery.

FIG. 20 is a flow chart illustrating the switching architecture forenergizing successive propulsion windings along a guideway for thesystem of the invention for electrical power storage and delivery.

FIG. 21 is a schematic diagram illustrating the (x, y) geometry forenergizing guideway propulsion blocks for the system of the inventionfor electrical power storage and delivery.

FIG. 22 is a schematic diagram illustrating the sequence for energizingpropulsion blocks along a guideway for the system of the invention forelectrical power storage and delivery.

FIG. 23 is a schematic diagram of (x, y) switch geometry for the systemof the invention for electrical power storage and delivery.

FIG. 24 is a schematic diagram of (x, y, z) switch geometry for thesystem of the invention for electrical power storage and delivery.

FIG. 25 is a graph illustrating the magnetic lift force from iron platesin a guideway beam for the system of the invention for electrical powerstorage and delivery, as a function of vehicle magnet current andfractional coverage of iron plates.

FIGS. 26A, B and C illustrate the guideway loop panel layout forvertical stability of the energy storage vehicle of the invention, atvertical equilibrium, above vertical equilibrium, and below verticalequilibrium.

FIGS. 27A, B and C illustrate the guideway loop panel layout for lateralstability of the energy storage vehicle of the invention, at lateralequilibrium, close to the guideway beam, and far from the guideway beam.

FIG. 28 is a cross-sectional schematic diagram of a guideway arrangementfor switching energy storage vehicles to a siding when not in use forstorage or generation of electric power.

FIG. 29 is a top view of the guideway arrangement of FIG. 28 forswitching energy storage vehicles to a siding when not in use forstorage or generation of electric power.

FIG. 30A is a top cross-sectional view of an underground shaft with anenergy storage vehicle and guideway panels in a vertical shaft for thesystem of the invention for electrical power storage and delivery.

FIG. 30B is a side cross-sectional view of the underground shaft with anenergy storage vehicle and guideway panels in a vertical shaft as shownin FIG. 30A.

FIG. 31 is a schematic diagram of unloading and loading equipment forstorage masses using a vertical guideway in the system of the inventionfor electrical power storage and delivery.

FIG. 32 is a schematic diagram illustrating the storage field geometryand dimensions for a vertical shaft guideway in the system of theinvention for electrical power storage and delivery.

FIG. 33A is an end view illustrating the process of lifting a storagemass from an energy storage vehicle according to the system of theinvention for electrical power storage and delivery.

FIG. 33B is a top view illustrating the process for lifting a storagemass from an energy storage vehicle according to the system of theinvention for electrical power storage and delivery.

FIG. 34 is a schematic diagram illustrating the transfer of storagemasses from an unload/loading beam to an on-grade rail support system.

FIG. 35 is a schematic diagram of an illustrative storage field geometryand dimensions according to the system of the invention for electricalpower storage and delivery.

FIG. 36 is a schematic diagram showing an illustrative unloading patternfor storage masses according to the system of the invention forelectrical power storage and delivery.

FIG. 37 is a flow chart illustrating different alternate embodiments forstoring and delivering electrical energy according to the system of theinvention for electrical power storage and delivery.

FIG. 38 is a cross-sectional view illustrating the iron lift andinductive loop arrangement of the system of the invention for electricalpower storage and delivery.

FIG. 39 is a cross-sectional view illustrating the iron lift andconducting sheet arrangement of the system of the invention forelectrical power storage and delivery.

FIG. 40 is a schematic, sectional view illustrating an energy storagevehicle on a planar guideway.

FIG. 41 is a schematic, sectional view illustrating an energy storagevehicle utilizing superconducting quadrupole magnet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As is illustrated in the drawings, the invention is embodied in a newapproach for the storage and rapid delivery of electric power, based onmaglev technology. This new system of the invention for electrical powerstorage and delivery utilizes maglev vehicles to lift storage massesdistances such as a kilometer or more in altitude. In doing so, a largeamount of electrical energy is drawn out of the power grid and stored asgravitational potential energy. Raising a 100 ton mass two kilometers inaltitude, for example, stores 0.5 MWH of energy.

A 100 meter×600 meter long (6 acres) storage facility could handle anddeliver 2000 storage masses, equivalent to 1000 MWH of electricalenergy. Overall energy efficiency, output electrical energy/inputelectrical energy, would be well above 90%—much higher than any otherelectrical storage technology. Facilities for the system of theinvention for electrical power storage and delivery could be erected ina short time, e.g., 3 years or less, to meet increasing peak powerdemands. Raising 2000 such masses would store 1000 MWH of energy, whichwould be returned to the power grid at appropriate times by simplytransporting the masses down to a lower altitude. During periods ofelectrical storage, a maglev vehicle would carry masses up to a higheraltitude storage facility, with the vehicle operating in the motor modeas shown in FIGS. 3A and 3B, showing schematic diagrams of the conceptof the system of the invention for electrical power storage anddelivery. During periods of electrical power delivery, the storagemasses would be carried down to lower altitude, with the vehicleoperating in the generator mode.

As is illustrated in FIGS. 3A and 3B, in one presently preferredembodiment of the electrical power storage and delivery system 50according to the invention, maglev vehicles 52 transport heavy storagemasses 54, such as 100 ton unit masses, for example, between the upperand lower ends of an inclined guideway 56. In the storage modeillustrated in FIG. 3A, electrical energy is taken from the grid topropel loaded vehicles 58 carrying the storage masses uphill. Thesemasses are unloaded at the upper end 60 of the heavyweight section 62 ofthe guideway, and the unloaded vehicles 64 return on the lightweightdownhill section 66 of the two way guideway 56. When it is desired todeliver electrical energy back into the grid, the direction of vehiclemovement on the guideway is reversed, as shown in FIG. 3B, and the emptyvehicles 68 are loaded with the storage masses positioned at the upperend of the guideway. The loaded vehicles 70 then transport the storagemasses down to the lower end 72 of the guideway where the masses areunloaded and positioned until the next energy storage period starts.

The electrical energy fed into the grid comes from the gravitationalpotential energy of the masses stored at the upper end of the guideway.The maglev propulsion windings on the guideway, which acted as anelectric motor during the energy storage phase, now act as an electricgenerator, converting the gravitational potential energy to electricalpower.

The system of the invention for electrical power storage and delivery isthe mechanical analogue of pumped hydro energy storage, using blocks ofsolid material rather than streams of water. It has a number ofimportant advantages over pumped hydro:

-   -   1. The system of the invention for electrical power storage and        delivery can be sited in a much wider range of locations.    -   2. The system of the invention for electrical power storage and        delivery can utilize a much greater change in elevation, i.e.,        thousands of feet instead of hundreds of feet. The pressure        changes over 6000 feet of elevation change with pumped hydro,        for example would be extremely large, on the order of 3000 psi.        It would be very difficult to build an efficient, low cost        pumped hydro unit under such conditions.    -   3. The system of the invention for electrical power storage and        delivery has a much smaller footprint, and much less        environmental impact, than pumped hydro.    -   4. The system of the invention for electrical power storage and        delivery has a much greater overall efficiency (electrical        output/electrical input) than pumped hydro. The system of the        invention for electrical power storage and delivery can achieve        overall efficiencies approaching 100%.    -   5. The system of the invention for electrical power storage and        delivery can respond very rapidly to fluctuations in load        demand, and be efficient over a wide range of power inputs and        outputs.    -   6. The system of the invention for electrical power storage and        delivery is very attractive in combination with solar and wind        power.    -   7. The cost of energy storage for the system of the invention        for electrical power storage and delivery will be low, compared        to other systems.

The total energy delivered is determined by the number of storage massescarried up and down, while the power delivered is determined by the rateat which they are carried.

FIG. 4 illustrates the amount of energy that can be stored by raising a100 ton mass—a representative load for a vehicle for use in the systemof the invention for electrical power storage and delivery—for a 2000meter change in elevation. Taking electrical inefficiencies intoaccount, the system of the invention for electrical power storage anddelivery would draw about 0.56 MWH from the grid in the storage mode andreturn about 0.52 to it in the power delivery mode.

FIG. 5 shows the operational flowsheet for the system of the inventionfor electrical power storage and delivery. The system of the inventionfor electrical power storage and delivery is extremely flexible. It canaccept power from the grid at any time, and deliver it at any time.Moreover, it can standby for an indefinite period without loss of energyand energy delivery capability. It can start up or shutdown in a veryshort time, under a minute with no operational problems. It can alsochange the rate at which it accepts or delivers power in a very shorttime.

FIGS. 6A–6D illustrate the types of locations where a system accordingto the present invention could be sited. FIG. 6A illustrates a guidewaylocated on a surface providing a natural elevation change. FIG. 6Aillustrates a guideway located on a surface providing a naturalelevation change. FIG. 6B illustrates a guideway located in a slantedtunnel. FIG. 6C illustrates a guideway located in a vertical mine shaft.FIG. 6D illustrates a guideway located on a natural surface elevationchange and a slanted tunnel. In regions with elevated terrain, such asCalifornia, Washington, Oregon, the Southwest, Hawaii, Japan, France,Switzerland, and portions of Russia, China, India, and the like,inclined guideways could be used, with the incline angle being in therange from about 30 to 50 degrees. Elevation changes in these regionswould probably range from about 1000 to 3000 meters. In flat plain typeregions, such as Florida, the South East, Mid West, New York New Jersey,and portions of Europe, Russia, China, India, and the like, whereelevation changes are generally below 1000 meters, the system of theinvention for electrical power storage and delivery could be located insub-surface tunnels. Tunnel depths of up to 2000 meters are readilyachieved in underground mines and could be constructed in most of theworld. These tunnels could be inclined or vertical shafts depending onthe terrain. Finally, the system of the invention for electrical powerstorage and delivery could be located using a combination of aninclined, above—surface guideway and an inclined, sub-surface tunnel.Such a combination would provide a greater elevation change, e.g., 4000meters instead of 2000 meters, and more energy storage capability perton of mass weight.

There are substantial differences between a passenger/freight vehicleand a vehicle for energy storage:

-   -   1) Passenger/freight vehicles operate over a range of AC        propulsion frequencies, not just the 60 Hertz value for the        system of the invention for electrical power storage and        delivery.    -   2) Vehicles used in the system of the invention for electrical        power storage and delivery must climb steep grades making the        propulsion force comparable to vehicle weight. In the        passenger/freight application, the propulsive force is only        about 10% of vehicle weight.    -   3) The weight per unit length of vehicle is much greater for        vehicles used in the system of the invention for electrical        power storage and delivery than for passenger/freight vehicles.    -   4) The speed of vehicles used in the system of the invention for        electrical power storage and delivery is much less than        passenger/freight vehicles.

FIGS. 7A and 7B show a typical propulsion loop/vehicle magnetconfiguration for a passenger/freight vehicle 74 which typically carriesvehicle quadrupole magnets 76. The guideway beam box 78 carries theguideway propulsion windings 80. The length/width ratio of thesuperconducting vehicle magnet loops is substantially greater than one.This is because the long sections of the vehicle superconducting and theguideway loops provide magnetic lift and stability forces, while theshorter width sections and cross-over windings of the vehicle andguideway loops provide the magnetic propulsive forces, which are smallcompared to the lift and stability forces.

The situation is different for the vehicles for use in the system of theinvention for electrical power storage and delivery, as illustrated inFIGS. 8A and 8B. The vehicle 74 typically carries vehicle dipole loops82, and the guideway beam box 78 may carry iron plates 84 to assistlift, in addition to the propulsion windings 80 (shown in FIG. 8B). Herethe ratio of the loop length/loop width is substantially less than 1, inorder to maximize the magnetic propulsive force, and to keep the magnetpitch relatively small so that 60 Hertz AC current can be used in thepropulsion windings.

The maglev technology for energy storage has certain similarities tothat for passenger and freight transport, but there are also importantdifferences. These differences include:

-   -   1. much steeper grade for the energy storage guideway;    -   2. requirement for constant vehicle speed and constant grade for        the energy storage guideway;    -   3. considerably greater vehicle loads for the energy storage        guideway;    -   4. much shorter vehicle lengths for the energy storage guideway;    -   5. rapid loading and unloading of heavy storage masses from        vehicles for the energy storage guideway; and    -   6. large ratio of load vehicle mass to unloaded vehicle mass for        the energy storage guideway.

As a result of these differences, the design of the vehicle and guidewayfor use in the system of the invention for electrical power storage anddelivery differs substantially from that for passenger and freighttransport. First, the much steeper grades for the system according tothe present invention (45 degrees or more, versus a maximum of about 10degrees for passenger/freight transport), together with the considerablyheavier vehicles (about 100 tons vs a maximum of about 50 tons forfreight transport) necessitates much greater propulsion forces, i.e., afactor of 10 or more.

Second, passenger/freight maglev vehicles will operate over a range ofspeeds and grades on the guideway depending on local conditions. Theirmaglev propulsion systems can accommodate these varying conditions bychanging the frequency and current delivered by the AC power in thepropulsion windings.

In order to efficiently levitate the short heavy vehicle with minimumI²R losses, iron plates incorporated into the narrow beam guideway canassist the levitation force, with null flux loops used for stability andoscillation damping. Depending on system design, iron lift assistancemay or may not be employed.

FIGS. 9A and 9B show the baseline configuration for a vehicle 52 for usein the system of the invention for electrical power storage and deliveryin its loaded and unloaded state. The vehicle has a flat upper surface86 on which a heavy (about 100 ton) reinforced—concrete block 54 isquickly loaded and unloaded. The concrete block is held in place by aquick acting locking mechanism (e.g., pins or straps or bars) betweeniron plates on the bottom of the block and DC current windings on thetop of the vehicle or by magnetic attractive forces. The vehicle for usein the system of the invention for electrical power storage and deliveryis a simple structure of steel I-beams, and plates to which are attacheda series of superconducting dipole magnets 82. Total vehicle length isshort, typically in the range of 5 to 10 meters.

As is shown in FIGS. 9A and 9B, the storage masses 54 are simplereinforced large concrete blocks placed on the flat upper surface 86 ofthe vehicle the system of the invention for electrical power storage anddelivery. Typical dimensions for a 100 ton storage mass are 3.5 metersin width, 2.5 meters high, and 4.5 meters in length.

The vehicle rides along a narrow beam guideway 88 (FIG. 10) consistingof a hollow concrete box beam to which a series of panels 90 isattached. Each panel contains a set of passive aluminum wire loops (1,2, 3, 4) to provide passive vertical and lateral stability, along withpropulsion windings that are connected to the external electric powergrid. When the system of the invention for electrical power storage anddelivery operates in the energy storage mode, net electric power flowsinto the set of propulsion windings, while when the system of theinvention for electrical power storage and delivery operates in thepower delivery mode, electric power flows out of the propulsionwindings.

Iron lift plates 84 are typically attached to the narrow beam guideway88. If present, they are positioned so that the magnetic attractionbetween them and the superconducting dipoles on the vehicle providevirtually all of the lift force needed to support the vehicle. Byitself, this attractive suspension force is vertically unstable;however, the combination of the iron lift plates and the assembly ofnull flux aluminum loops in the side panels on the guideway beam has anet stability. That is, if an external force causes the vehicle to moveupwards from its equilibrium suspension point, a net magnetic forcedevelops to push the vehicle downwards towards its equilibrium point;conversely, if the vehicle moves downwards from its equilibrium pointdue to an external force, a net magnetic force develops to push thevehicle upwards to the equilibrium point. If the iron left plates arenot used, the guideway aluminum loops by themselves provide thenecessary vertical lift and stability forces, together with the lateralstability forces.

FIG. 11 shows the layout of the energy storage facility according to thesystem of the invention for electrical power storage and delivery. Theguideway 56 has end loops 92 at the upper and lower ends (60, 72) of thetwo way guideway. The end loops enable the vehicles to rapidly traversethe entire guideway, minimizing the number of vehicles needed to storeor deliver a given amount of power. Storage masses 54 in the vehiclemass yard 94 are unloaded and loaded from locations along the endguideway loops, using rapid handling equipment.

For those times when the power demand is less than the maximum powercapability, the vehicles not engaged in storing or delivering power willbe stationed on sidings 96 at the upper and lower ends of the guideway.When needed to boost operating power level, vehicles will be quicklywithdrawn over the guideway switches 98 from the two sidings to jointhose already operating on the guideway. The time required to startoperating is less than a minute.

The amount of lift force provided by the iron plates is controlled byhow many iron plates (and also how thick they are) are located on theguideway. On the section of the guideway shown in FIGS. 3A and 3B, wherethe vehicle transports the heavy storage mass (either up or down,depending on whether the system of the invention for electrical powerstorage and delivery is in the power storage or power generation mode),more iron plates are used, since the weight of the vehicle plus itsstorage mass will exceed 100 tons. Referring to FIGS. 3A and 3B, in thesection of the guideway where the empty vehicle travels up or down, thenumber of iron plates is much less, since the empty vehicle weighs onlyabout 10 tons.

The number of vehicles is determined by the maximum power rating of thefacility for use with the system of the invention for electrical powerstorage and delivery (the greater the power capability desired, the morevehicles will be needed), and the time required for a vehicle to make afull traverse of the complete guideway circuit, including the time tounload and load as storage mass (the shorter the time, the fewervehicles will be needed).

TABLE 1 Illustrative Power Inputs and Outputs Basis: 100 Ton Net MassPer Vehicle 60 Meter/Sec Speed (134 mph) Guideway Inclination, DegreesNumber of 30 45 90 Vehicles on Power Spacing Power Spacing Power SpacingGuideway (MW) (Km) (MW) (Km) (MW) (Km)  1 30 4 40 2.8 60 2  2 60 2 801.4 120 1  4 120 1 160 0.7 240 0.5  8 (2 240 1 320 0.7 480 0.5  connected   vehicles) 12 (3 360 1 480 0.7 720 0.5   connected  vehicles)

Table 1 above shows the power capability of a facility according to thesystem of the invention for electrical power storage and delivery basedon the number of vehicles operating on the power section of the guideway(i.e., the section that handles the vehicles that carry 100 ton storagemasses), and the angle of incline for the guideway. A net mass of 100tons per vehicle (i.e., the weight of the storage mass) is assumed.Since the vehicles travel on both the up and down sections of theguideway, the net power demand related to the vehicle mass isessentially zero.

A vehicle velocity of 60 meters per second is assumed. This velocitycorresponds to a magnet pitch of 1 meter and an AC power frequency of 60Hertz. The steeper the guideway, the more power is generated pervehicle. This is a result of a faster rate of change in elevation whenthe guideway incline becomes steeper.

The facility according to the system of the invention for electricalpower storage and delivery can store or deliver 480 MW(e) at an inclineangle of 45 degrees if there are 12 vehicles operating on the powersection of the guideway. Assuming that 3 vehicles are hooked together toform a consist, the corresponding distance between consists would thenbe 0.7 kilometer.

DESCRIPTION OF THE SYSTEM OF THE INVENTION FOR ELECTRICAL POWER STORAGEAND DELIVERY USING ANGLED ON-GRADE GUIDEWAYS Description of a BaselineSystem

The analytical relationships that affect the choice of optimum speed fora facility for the system of the invention for electrical power storageand delivery are set forth below:

Length of Vehicle Magnet:v=fλ;

-   -   f=frequency (i.e., 60 Hz);    -   v=speed, m/s;    -   λ=magnet pole pitch, meters    -   λ/2 =v/2 f    -   λ/2 =length of one superconducting loop on vehicle, m

Ratio, Vehicle Kinetic Energy/Delivered Electrical Energy:R ₁ =v ²/2 gΔh₀

-   -   Δh₀=change in elevation, meters

Height Change to Achieve Vehicle Operating Speed:${\Delta\; h_{1}} = \frac{v^{2}}{2\; g}$

Ratio, Energy Lost to Air Drag/Delivered Electrical Energy:R*=½C _(D)ρ_(AIR) A _(F) V ² /m _(g) sin θ

-   -   C_(D)=Drag coefficient;    -   A_(F)=Frontal Area, m²;    -   M=Delivered mass, kg;    -   θ=Angle to Horizontal

The first decision point is whether the propulsion system should operateat an AC frequency of 60 Hertz, or at some other frequency. If thefrequency of 60 Hertz is selected, it minimizes the cost of theequipment needed to handle the large blocks of power that come into thefacility for the system of the invention for electrical power storageand delivery from the grid during the energy storage period, and that goout of the facility to the grid during the power delivery period. The 60Hertz choice enables the facility to operate using simple transformersthat step down the voltage from the grid to match that in the propulsionwindings. The speed of the vehicles and pitch of its magnet are chosento match the frequency and phase angle of the AC grid power. If thepropulsion frequency is different from 60 Hertz, then frequencyconversion equipment is needed to change the AC power frequency to thatused to propel the vehicles (in the motor mode) and to change thefrequency of the power delivered by the generator mode to match that inthe external power grid. However, the use of an asynchronous DC/AC linkbetween the maglev energy storage system and the electrical grid allowsgreater system flexibility, in that vehicle speed and inclination anglecan vary along the guideway and that transients associated with vehiclesentering and leaving the guideway are more readily handled. The choiceof operating at 60 Hertz in synchronism with the external grid, orasynchronously with DC/AC conversion will depend on the particularconditions of the site and the external grid.

FIG. 12 shows the effect of vehicle speed on the performance of thesystem of the invention for electrical power storage and delivery.Higher speeds decrease the magnet pitch length, as 1/V, if frequency isto be kept constant at 60 Hertz. Moreover, higher speeds increase theequivalent Δh needed to achieve operating speed. If Δh becomescomparable to the change in elevation for the guideway, the kineticenergy of the moving loaded vehicle becomes comparable to the electricalenergy stored by the raising of the transported mass. In addition, theair drag losses increase as the square of vehicle speed. The optimumvehicle speed is chosen to be 60 meters per second. This speedcorresponds to a magnet pitch of 1 meter, which is short enough for anefficient propulsion motor/generator, but long enough that there can bea substantial physical gap between the vehicles and the guideway.Moreover, 60 meters per second is slow enough that the value of Δh isrelatively small, 180 meters, compared to the 2000 meters elevationchange. In addition, the air drag losses are only about 1% of the energystored and delivered by the vehicle. If an asynchronous AC/DC link tothe external grid is used, the vehicle speed can be chosen independentlyof the magnet pitch.

FIG. 13 shows the position and speed of the vehicle in the baselinepower storage cycle. A time interval of 100 seconds is assumed for theunloading of the storage mass from the vehicle for the system of theinvention for electrical power storage and delivery, and an equalinterval of 100 seconds for the loading of the storage mass. As shownlater, these time intervals appear quite conservative. It is very likelythat the unloading and loading processes can be carried out in muchshorter time.

The vehicle for use in the system of the invention for electrical powerstorage and delivery is stationary during the loading and unloadingportions of the cycle. There are two short acceleration periods of 8.5seconds each—the vehicle accelerates after the mass is unloaded and alsoafter it is loaded—and two short deceleration periods, also of 8.5seconds each.

TABLE 2 Number of Round Trips Per Hour vs. Vehicle Speed and GuidewayAngle Vehicle Speed (m/sec) 60 50 40 Guideway Inclination (deg) 45 30 4530 45 30 Unload and Load (sec) 200 200 200 200 200 200 Ascend 2000Meters (sec) 47.2 66.7 56.6 80 70.8 100 Descend 2000 Meters (sec) 47.266.7 56.6 80 70.8 100 Accelerate and Decelerate 4 34 34 28 28 23 23Times (sec) Total (sec) 328 367.4 341.2 388 365 423 Round Trips per Hour11 9.8 10.6 9.3 9.9 8.5

Table 2 above shows the number of round trips carried out per hour by avehicle, based on the time periods described above, as a function ofvehicle speed. The number of round trips is also shown in FIG. 14.

With a load time of 100 seconds, an unload time of 100 seconds, and a 2kilometer ascend/descend net distance for energy storage and powergeneration modes, at 60 meters per second, 10 round trips per hour canbe carried out. The number of round trips is insensitive to theinclination angle of the guideway. This is a consequence of relativelylong periods assumed for loading and unloading the vehicles, compared tothe short acceleration and deceleration periods, and to the short traveltime on the inclined guideway.

FIG. 15 shows the magnetic geometry used to calculate the magneticpropulsive forces and power for the vehicle, while the analyticrelationships employed are set out below.Fp(t)=2By(t)I _(G)(t)l _(P)=2(By)*sin wt(I _(G))*sin (wt+λ)[l_(P)]Newtons

The factor of 2 reflects the effective doubling of current in thepropulsion winding cross-overs, with w=2πf radians per second;

-   -   f=60 Hertz;    -   λ=Phase angle between propulsion current and By magnetic field        acting on propulsion winding;    -   (By)*=Maximum magnetic field experienced by propulsion winding,        Tesla;    -   (I_(G))*=Maximum current in guideway propulsion loop winding,        amp turns;    -   l_(P)=Total length of propulsion windings acted on by magnetic        field from vehicle magnets, meters;

The time averaged propulsion force resulting from the sine wave fieldand current is: $\quad\begin{matrix}{{\overset{\_}{F}}_{P} = {(2)\left\{ \frac{{B\; y^{*}I_{G}^{*}{\int_{0}^{2{\pi/w}}{\left\lbrack {\sin\; w\; t} \right\rbrack\sin\; w\; t\;\cos\;\lambda}}}\  + {\cos\; w\; t\;\sin\;\lambda\;\phi{\mathbb{d}t}}}{\int_{0}^{2\pi\; w}{\mathbb{d}t}} \right\} l_{P}\mspace{20mu}{Newtons}}} \\{= {{(2)\frac{B\; y^{*}I_{G}^{*}}{2}\cos\;{\lambda\left( l_{P} \right)}} = {B\; y^{*}I_{G}^{*}\;\cos\;{\lambda\left( l_{P} \right)}}}}\end{matrix}$

The average propulsion force equals the force required to keep theloaded energy storage vehicle moving up the inclined guideway at avelocity V and angle θ.{overscore (F)} _(P)=(M _(v) +M _(mass))g sin θ=M _(TOT) g sin θ

Combining the two equations, the peak guideway propulsion current isgiven by:I* _(G) =M _(TOT) g sin θ/By*cos λ(l _(P))amp turnswith the rms value of I_(G) being (I_(G))_(RMS)=0.707 I_(G)*

The total length of the propulsion winding is given byl_(P)=N_(M)l_(M) meterswhere N_(M)=number of superconducting magnet loops on the vehicle (1loop per polarity −2 loops for a pair of + and − polarity) andl_(M)=length of propulsion winding in the loop

As an example, for l_(M)=1 meter, and N_(M)=20 (5 pairs superconductingloops on each side of the vehicle), l_(P)=20 meters.

The actual system and method for storage and generation of electricalenergy will have a three phase propulsion winding, with each phasecarrying one third of the total current required to propel the vehicle.Accordingly,(I _(G))*_(3φ)=⅓I _(G)*and[(I _(G))_(RMS)]_(3φ)=⅓(I _(G))_(RMS)

Per phase, the I²R losses in the propulsion windings are then:$\left( {I_{G}^{2}R} \right)_{3\phi} = {\left\lbrack {\left( \frac{I_{\theta}}{3} \right)R\; m\; s} \right\rbrack^{2}{\frac{\rho_{A1}}{A_{A1}}\left\lbrack {1 + \frac{W_{P}}{l_{P}}} \right\rbrack}\left( l_{P} \right)\left( \frac{l_{E\; P}}{l_{P}} \right)}$

Where

-   -   ρ_(A1)=Resistivity of aluminum conductor=2.8×10−6∩ cm;    -   A_(A1)=Cross sectional area of aluminum conductor, cm²;    -   W_(P)/l_(P)=Ratio of propulsion loop width/length        [W_(P)/l_(P)=0.5];    -   l_(EP)/l_(P)=Ratio of length of energized propulsion        winding/length of propulsion winding under vehicle.

The total I²R power in the propulsion winding is:P _(TOT)=3P(I ² R)_(3φ)=3[(I _(G) ² R)_(3φ)]

These analytic relationships are derived based on the magnetic fielddistributions for an infinitely long bifilar (i.e., parallel wire)electrical circuit, so that the results are somewhat approximate,because they do not include end effects from the ends of the magnetloops. However, they are accurate enough for the purposes of describingthe system of the invention for electrical power storage and deliveryand scoping out its overall performance capabilities.

FIG. 16 illustrates the vector addition of the lift and propulsionforces in the guideway for the system of the invention for electricalpower storage and delivery. The propulsion and magnetic lift forcesneeded are set out in table 3 below.

TABLE 3 Vector Addition of Magnetic Propulsion and Magnetic Lift ForcesLoaded Vehicle Unloaded Vehicle [110 Metric Tons] [10 Metric Tons]Guideway Inclination (θ, deg) 30 45 90 30 45 90 Magnetic  5.4 × 10⁵ 7.62× 10⁵ 1.08 × 10⁶ 4.9 × 10⁴ 6.93 × 10⁴ 9.8 × 10⁴ Propulsive Force,Newtons Magnetic Lift  9.4 × 10⁵ 7.62 × 10⁵  0 8.5 × 10⁴ 6.93 × 10⁴  0Force, Newtons Total Gravity 1.08 × 10⁶ 9.8 × 10⁴ Force, Newtons

For a vertical shaft system for electrical power storage and delivery(θ=90 degrees) the lift and propulsion forces are the same, since thegravity vector acts downwards along the shaft. For inclined guideways,the iron lift plate magnetic vector and the magnetic propulsion vectoradd together to counter the vertically downwards gravity vector actingon the vehicle.

TABLE 4 Numerical Values for By Components as a Function of Y₀ and ZBasis: W = 50 Centimeters Y₀ = 15 cm (5.9 Inches) Y₀ = 18 cm (7.1Inches) Term Z = 8 Z = 16 Z = 25 Z = 8 Z = 16 Z = 25 Z/Z² + Y₀ ² +0.0277+0.0333 0.0294 +0.0206 +0.0276 +0.0263 −(Z + W)/(Z + W)² + Y₀ ² −0.162−0.0144 −0.0128 −0.0157 −0.0141 −0.0126 +(Z + 2W)/(Z + 2W)² + Y₀ ²+0.0091 +0.0085 +0.0079 +0.0090 +0.0084 +0.0078 +(W − Z)/(W − Z)² + Y₀ ²+0.0211 +0.0246 +0.0294 +0.0201 +0.0230 +0.0263 +(2W − Z)/(2W − Z)² + Y₀² −0.0106 −0.0115 −0.0128 −0.0105 −0.0114 −0.0126 +(3W − Z)/(3W − Z)² +Y₀ ² +0.0070 +0.0074 +0.0079 +0.0069 +0.0073 +0.0078 SUM +0.0381 +0.0479+0.0490 +0.0304 +0.0408 +0.0430

Table 4 above and FIG. 17 show how the magnitude of the magnetic fieldBy component (i.e., the component normal to the plane of thesuperconducting dipole loop on the vehicle) varies with distance z alongthe vehicle and separation y_(o) between the plane of thesuperconducting vehicle loop and the guideway propulsion loop.

Note that By=0 at z=0 (directly under one superconductor) and z=50centimeters (directly under the adjacent superconductor), and is amaximum at By−25 centimeters. The 50 centimeter distance betweensuperconductors corresponds to a magnet pitch of 100 centimeters (=1meter), the value decided on earlier. The magnitude of By shown in FIG.17 repeats every 50 centimeters, but with an opposite sign.

Also note that By is almost a perfect sine wave over the interval z=0 toz=50 centimeters. (The deviations are shown as shaded areas.) Withslight changes in placement of the superconducting cables, and/or localplacement of iron flux guides, a perfect 60 Hertz sine wave could beachieved. This is important in terms of matching the frequency and phaseof the propulsion power input/output to that of the external power grid.

Also shown is the effect of increasing the vertical separation, y₀,between the plane of the superconducting guideway loop and the plane ofthe superconducting magnet. The magnitude of the By component decreaseswith increasing y₀, but the shape continues to be close to that of asine wave.

FIG. 18 illustrates the phase angle difference between the propulsioncurrent and the By magnetic field component. With a phase angle of zerodegrees, the propulsion force is at its maximum possible value as phaseangle increases, propulsion force decreases. By operating at asubstantial non-zero value for the phase angle, one ensures that thepropulsion system can automatically adjust to, and compensate for,variations in wind force, drag coefficient, and the like, withoutaffecting the synchronicity and constant frequency nature of thepropulsion system for the system of the invention for electrical powerstorage and delivery.

TABLE 5 Numerical Values of Propulsive Current as a Function of Numberof Magnet Pairs Basis: 110 Tons Total Vehicle Mass (100 + 10 = 110 Tons)45 Degrees Angle Guideway 7 Inch Vertical Separation 30 Degree PhaseAngle (λ) 1 Meter Winding Length (lm) Total Length Number of of MagnetsMagnet Pairs Along Each I_(G)* (Amp Turns) (Both Sides) Side (Meters)800 KA Magnet 600 KA Magnet 12 6 53,000  71,000 10 5 64,000  85,000 8 480,000 107,000 6 3 107,000  142,000 Note: For a three phase propulsionwinding, (I_(G)*)_(3P) = 1/3 I_(G)*

Table 5 above shows the magnitude of the current in the guidewaypropulsion loops needed to propel a loaded vehicle uphill, as a functionof the number of superconducting magnet pairs on the vehicle (one magnetpair corresponds to a full pitch of one meter, which has two loops ofalternating polarity) and the level of current in the superconductingmagnets. Note that the total of 10 magnet pairs for the vehiclecorresponds to having 5 magnet pairs on each side of the vehicle.

The values of guideway loop current shown in Table 5 correspond tohaving a connected set of guideway single phase loops with the loops onthe left side of the vehicle in series with the loops on the right side.All loops carry the same single phase current.

In practice, the electrical power grid operates on a three phase currentarrangement. Accordingly, a three phase propulsion current arrangementis required for the system of the invention for electrical power storageand delivery. FIG. 19 shows this arrangement of superconducting loops onan energy storage vehicle, in which the three separated propulsionwindings each carry one phase. In FIG. 19, phases A, B and C are shownas having different widths for clarity of presentation. They actuallywill have essentially the same widths. The currents in the Phase A, Band C windings are not in phase, but are timed to give propulsion forcesin the left direction. The physical separation between the threewindings corresponds to an electrical separation of 120 degrees, witheach winding operating at the same phase angle between the magneticfield By from the superconducting magnet and the propulsion current.Each of the three windings carries ⅓ of the total current shown in Table5 for a given combination of the number of superconducting magnet pairsand the current in the magnets.

TABLE 6 I²R Losses in Propulsion Windings as a Function of the Number ofMagnet Pairs Basis: Ac = 39 cm² [2″ × 3″ Cross Section], 1 Meter WindingLength w_(P)/l_(P) = 0.5, θ = 45 Degrees, 110 Ton Vehicle Mass 900 KAMagnet Current, 30 Degree Phase Angle, 7 Inch Separation 8 10 12Parameters l_(EP)/l_(P) = 2 4 2 4 2 4 I_(G)*, KA 80 → 64 → 53 →(I_(G))_(RMS), KA 56.6 → 45 → 37.5 → [(I_(G))_(RMS)]_(3θ), 18.8 → 15 →12.5 → KA l_(P), Meters 16 → 20 → 24 → P(I²R)_(3θ), KW 122 244 97 194 81162 P_(TOT), KW 366 732 291 582 242 448

The corresponding I²R losses in the propulsion windings are shown inTable 6 above, as a function of the total number of magnet pairs on thevehicle, and the length of the guideway block that is energized at anygiven time. Two values of block length energization are shown, withl_(EP)/l_(P) values of 2 and 4 (l_(EP)/l_(P) block energizationlength/vehicle length).

The I²R losses are all well below 1 megawatt. These are small comparedto the 40 megawatt power input/output levels for the loaded vehicle, sothat the propulsion systems is very efficient. There clearly is a strongincentive to have a short energization block length, i.e.,l_(EP)/l_(P)=2, rather than a longer one. The I²R losses decrease as thenumber of magnet pairs, and consequently LP, increase, because theeffect of greater winding length is offset by the smaller current levelneeded in the propulsion windings. With 10 magnet pairs andl_(EP)/l_(P)=2, the I²R propulsion loss for a loaded vehicle is onlyabout 300 kilowatts—less than 1% of the 40 MW power input/output.

The I²R propulsion losses associated with propelling the unloadedvehicle can be neglected. The propulsion current for the unloadedvehicle is a factor of 10 lower than that for the loaded vehicles,resulting in an I²R loss that is 100 times lower. The much lowerpropulsion current is due to the mass of the unloaded vehicle being onlyabout 1/10th that of the loaded vehicle.

An important feature of the system of the invention for electrical powerstorage and delivery is the unique propulsion switch architecture. Witha short energized block length and three phase propulsion windings, onewould need many hundreds of electronic switches to channel current intoand out of the propulsion windings that were individually connected tothe AC power grid.

Instead, a multi-dimensional switch architecture is used. In the twodimensional configuration, each block is connected to the propulsioncurrent control (FIG. 20) by two switch lines (x_(i), y_(j)). In FIG.20, one phase is shown; the other two phases are similar. As shown inFIG. 21, illustrating a grid of 100 propulsion blocks 100, 20 switches(10 x_(i) and 10 y_(j) switches) are sufficient to select any individualblock in the grid. Generalizing, the total number of switches isswitch#=2(# of blocks)^(1/2)

Thus, a grid of 900 blocks would require only 60 switches.

FIG. 22 shows how the energized blocks would operate in the case wheretwo sequential blocks were energized to propel the vehicle, in anexample such as where there are five magnet pairs per vehicle per side(5 meters total length), the propulsion block length is 5 meters, and amaximum of two blocks are energized. Energization is shown for one phaseonly. When the vehicle was traversing the Nth and N+1 propulsion blocks,both would be energized. When the vehicle had advanced to the pointwhere it was on just the Nth block, only that block would be energized.As the vehicle moved further, it would be on both the N−1 and Nth block,and both would then be energized.

TABLE 7 Number of Switches Basis: Two kilometer elevation change (2.83km total upwards length) θ = 45 Degrees Propulsion loops on the twosides of vehicle connected together (X, Y) switch geometry Number ofMagnet Pairs on Vehicle 8 10 12 Parameters l_(EP)/l_(P) = 2 4 2 4 2 4 #of Propulsion 708 354 566 283 472 blocks in 2.83 km up length, per phase# of switches per 54 27 48 24 44 22 phase in 2.83 km Total # of 162 81144 72 132 66 Switches for 3 phases in 2.83 km Total # of 324 162 288144 264 132 switches for 3 phases in 5.66 km (up & down sections)

Table 7 shows the total number of switches required for the 2.83kilometer long power input/output section of the guideway for the systemof the invention for electrical power storage and delivery. For allthree phases of the propulsion windings, only 72 switches would berequired, assuming l_(EP)/l_(P)=4 and 10 magnet pairs on the vehicle.

This is a very reasonable number of switches. If the energized blocklength were cut in half to l_(EP)/l_(P)=2, the number of switches wouldbe doubled to 144, a still very reasonable number.

The total number of switches for the up and down sections of the two wayguideway would be twice that for just the power input/output section,assuming that the energized block length were the same for bothsections. In fact, since the propulsion current in the return section isabout 1/10th of that in the power input/output section, the energizedblock length can be much greater, which would reduce the total number ofswitches to well below 100.

The number of switches can be further reduced by going to a threedimensional switch architecture, as illustrated in FIGS. 23 and 24,comparing the (x, y, z) switch geometry with (x, y) switch geometry. InFIG. 23, the connection to block 22 is made through switches (x2, y2).In FIG. 24, the third digit in location number refers to z planes whichare stabilized vertically in representation. Cables run vertically fromeach x, y location to their corresponding location in the z planes. Thatis, 211 is connected to 212, 213, 214, etc. Each z plane has its own setof y111, y211, y311, etc. switches. The block at 215, for example isenergized by switches x2 and y15. Using this connection pattern, 1000blocks could be individually selected with only (1000)⅓(3)=30 switches.A summary of the differences between the (x, y, z) switch geometry with(x, y) switch geometry is given in Table 8 below.

TABLE 8 (x, y) (x, y, z) Geometry Geometry Number of SuperconductingMagnet Pairs/ 10 10 Vehicle l_(EP)/l_(P) 2 2 Switches per phase (upsection) 48 27 Switches for 3 Φ 144 81 Total Number of Switches (up anddown 288 162 sections)

The total number of switches for this three dimensional architecture isgiven by the formula:# of switches=3 (# of blocks)^(1/3)

Thus, for a grid of 1000 blocks, only 30 switches would be required. Thechoice of the particular architecture used will depend on a number ofdetailed factors, which in turn will depend on the particular systembeing considered.

FIG. 25 shows the magnetic lift force provided by the iron lift platesas a function of the current in the superconducting magnets and thefractional longitudinal coverage of the guideway beam by the ironplates. For ten magnet pairs (1 meter width/pair), a total vehicle andstorage mass weight of 110 tons (i.e., on the power input/output sectionof the track), a 20 centimeter (8 inch) separation between thesuperconducting magnet conductor and the iron plate, and a 45 degreeguideway inclination, with the forces calculated by their magnetic imagerelationship, only about 25% of the guideway needs iron plate coverage.However, these calculations are idealized, in that: 1) the vehiclesuperconductor element is assumed to be an infinite wire of constantcurrent direction, rather than on assembly of finite length conductorsof alternating current direction, and 2) that the attractive forcebetween the superconductor and the iron plates is a pure image forcewith no allowance for edge effects due to the finite width of the ironplate, and no permeability saturation effects. However, there appears tobe a large lift force margin, so that full coverage by the iron plateswill not be required, even when the above force correction effects aretaken into account. With regard to the return section of the guidewaywhere the unloaded vehicle only weighs about 10 tons, the requiredfractional coverage by iron plates will be very small, probably lessthan 10 percent.

FIGS. 26A–C, showing vehicle vertical position, and 27A–C, showingvehicle lateral position, show the guideway loop arrangement forvertical and lateral stability of the vehicle for the system of theinvention for electrical power storage and delivery. These figure of 8(FIGS. 26A–C) and cross connected dipole (FIGS. 27A–C) null flux loopcircuits 102 are similar to those used for the passenger/freightapplication. Vertical and lateral stability is provided automaticallyand passively by induced non-zero currents 104 in the null flux loops ifthe vehicle moves upwards or downwards, left or right of its equilibriumsuspension point. When at its equilibrium point, there are no inducedcurrents in the null flux loops (the vehicle weight is balanced by theiron lift forces), and there are no I²R losses in the stability loops.I²R losses are generated if the vehicle departs from its equilibriumpoint, but these are small compared to those in the propulsion windings.

FIGS. 28 and 29 show the switching guideway 106 loop arrangement used toswitch vehicles from the main guideway 108 onto a siding 110 if they arenot needed to store or generate electric power for the external grid.Referring to FIG. 29, the vehicle will follow whichever line of theguideway loops, “A” or “B”, is activated. When needed, the stationaryvehicles would be switched off the siding and onto the main guideway.The switching step would be carried out when the vehicle was unloaded,on a planar section of guideway, not a narrow beam section. The switchsection has two overlapping lines of loops, one of which continues alongthe main guideway (which the transitions back to a narrow beamconfiguration) with the second leading to the siding. If the vehicle isto continue along the main guideway, electronic switches activate thefirst line of loops and open circuits the second line; if the vehicle isto go onto the siding) another set of electronic switches activates thesecond line of loops and open circuits on the first line. The switchsection is planar, with no projecting structure to obstruct vehiclemovement to either line of loops. The lift and stability forces areprovided by passive aluminum loops on the guideway. There are no ironlift plates.

Mechanical switching, in which the desired line of guideway loops isbrought into position, while the non-operating line of guideway loops isshunted aside, can also be used in place of electronic switching, ifdesired.

DESCRIPTION OF THE SYSTEM OF THE INVENTION FOR ELECTRICAL POWER STORAGEAND DELIVERY USING VERTICAL SHAFT GUIDEWAYS

The main differences between the system of the invention for electricalpower storage and delivery operating on an angled guideway and avertical shaft guideway are:

-   -   1) In the vehicle shaft guideway, all of the lift force on the        vehicle must be supplied by the propulsion winding. Iron lift        plates cannot be used to provide a partial lift force, as in the        angled guideway.    -   2) The narrow beam type guideway cannot be used to move the        vehicle vertically in the shaft guideway. Instead, guideway        panels on end side of the shaft have to be used to move the        vehicle vertically, and to stabilize it laterally.    -   3) Unloading and loading of the vehicle is done at one point at        the top and one point at the bottom of the vertical shaft,        rather than at a succession of points along the guideway, as was        done with the angled guideway.

FIGS. 30A and B show the layout of an energy storage vehicle 120according to the system of the invention for electrical power storageand delivery using a vertical shaft guideway 122. Each side of thevehicle has a line of superconducting dipole loops 124 that interactwith a line of guideway loop panels 126 on the sides of the verticalshaft. The vehicle typically has open sides 128 and closed sides 130. Asis explained further below, a gap 132 is provided between the vehiclestructure and the storage mass. The superconducting dipole loops are thesame as those for a vehicle operating on an inclined narrow beamguideway, except that instead of being located on the opposite sides ofa narrow beam, they are located on the opposite sides of the verticalguideway.

As is illustrated in FIG. 30B, the 100 ton storage mass is held in placeinside the vehicle according to the system of the invention forelectrical power storage and delivery, which is constructed of I-beamsas an open cage, by a set of retractable supports 132 positioned on theI-beams of the vehicle. The vehicle has a top 134 and a bottom 136, andthe weight of the storage mass is supported by the bottom of the vehiclecage.

TABLE 9 Numerical Values of Propulsion Current and I²R Losses as aFunction of Number of Magnet Pairs on an Energy Storage Vehicle in aVertical Shaft Guideway N_(m) (Number of Magnet Pairs) 8 10 12Parameters 2 4 2 4 2 4 I_(G)*, KA 113 → 90 → 75 → (I_(G))_(RMS), KA 80 →64 → 53 → [(I_(G))_(RMS)]_(3θ), KA 26.7 → 31 → 18 → l_(P), Meters 16 →20 → 24 → P(I²R)_(3Φ), KW 244  488 194  388 162 324 P_(TOT), KW 732 1464582 1164 484 896

Table 9 above shows the I²R losses in the propulsion windings for avertical shaft system according to the invention for electrical powerstorage and delivery as a function of the number of magnet pairs on thevehicle, and the length of the energized sections of propulsion windingson the guideway. These I²R losses are twice those for a vehicleaccording to the system of the invention for electrical power storageand delivery traveling on a narrow beam guideway at an incline angle of45 degrees (Table 6) because 100% of the vehicle weight in a verticalshaft guideway is supported by the propulsion winding rather than 70.7%of it, as is the case for a 45 degree guideway with iron lift plates.

Storage masses 54 are unloaded and loaded from the vehicle 120 using anoverhead trolley 138 of the type shown in FIG. 31. As with the storagemasses for the angled guideway, the overhead trolley has arms 139 withextendable struts 140 that fasten to the reinforced concrete storageblock 54, and lift it up off the base of the vehicle 120, and move itlaterally to the side. The I-beams 142 at the top of the vehicle cagehave retractable sections 144 that can swing aside to allow the storagemass to move laterally out of the cage.

The overhead trolley moves the storage masses on a track 146 for thewheels 147 of the trolley along a long transfer tunnel 148 in the rockwall 150 to the left or right of the loading/unloading point, as shownin FIG. 32. The two transfer tunnels have a number of side tunnels 152where the 100 ton masses are stored while not being moved up or down thevertical shaft guideway.

During the power generation phase, loaded vehicles according to thesystem of the invention for electrical power storage and delivery traveldown vertical shaft #1 converting gravitational potential energy intoelectric power. When the vehicle reaches the unload/load point in theshaft, the 100 ton storage mass is unloaded from the vehicle by thetrolley, which transfers the storage mass to a suitable point in one ofthe side tunnels.

The unloaded vehicle then drops below the unload/load point, and movessideways to vertical shaft #2, where it travels upwards to the surfaceunload/load point. There, a new 100 ton storage mass is loaded onto thevehicle, which then transfers back to vertical shaft #1. The vehiclethen travels downwards, generating further power.

The process reverses when the system of the invention for electricalpower storage and delivery takes electrical energy from the grid andstores it as gravitational potential energy of the 100 ton masses. The100 ton mass is then loaded onto a vehicle at the bottom of verticalshaft #1, and the loaded vehicle lifted up to the surface unload/loadpoint using electrical power drawn from the power grid. The 100 ton massis then lifted off the vehicle and stored in a yard at the surface. Theunloaded vehicle then moves laterally to vertical shaft #2, in which ittravels downwards to the bottom of the shaft. It then moves laterally tothe unload/load point at the bottom of shaft #1, where it picks up a new100 ton storage mass, and ascends to the surface again.

EXAMPLE System Parameters for Vertical Shaft Guideway

-   2 kilometer elevation change-   100 ton storage mass-   0.5 MWH stored per unit 100 ton mass-   90 degree inclination for guideway-   Below surface-   >90% energy storage efficiency (output/input)-   10 ton vehicle weight (unloaded)-   110 ton vehicle weight (loaded)-   60 meter/sec (134 mph) vehicle velocity-   10 round trips per hour for vehicle-   100 seconds to load or unload vehicles-   Dipole loop magnets along each side of vehicle-   1 meter magnet pitch (distance between loops of same polarity)-   10 magnet pairs per vehicle (5 on each side)-   0.5 meter loop width-   Vertical shaft guideway-   Figure of 8 null flux guideway loops provide lateral stability-   Dipole null flux guideway loops provide stability normal to    superconducting dipole loops-   60 hertz, three phase propulsion winding acts as motor to propel    loaded vehicle goes down the shaft, to return electric power to    grade

The example above summarizes the baseline system parameters for thevertical shaft guideway configuration. The angled guideway and verticalshaft guideway configuration can be developed in parallel so thatsystems can be implemented at a wide range of locations, both in flatterrain, and in terrain with substantial elevation changes. The vehiclemagnets and guideway panels are very similar. The vehicle configurationsare different, but this would not pose any problem

Loading and Unloading

FIGS. 33A and 33B show an illustration of equipment that could be usedto load and unload storage masses from the vehicles. It consists of twooverhead beams 146 with four extendable struts 140 that lock ontofastening means 154 such as projections or keyways at attachment pointsin the upper surface of the block. Alternatively, the struts couldcontain electromagnets that when energized, attract and stick to ironplates on top of the block, enabling it to be lifted.

Referring to FIG. 34, when the block is being unloaded, the strutsextend downwards and lock onto the block, and then lift it off the uppersurface of the vehicle. The vehicle then moves out, continuing along theguideway. At the same time, the block moves sideways along the overheadbeam, supported by wheels that ride on the beam.

The sequence is reversed during the block loading process. The block ismoved into position, the vehicle moves in under it, and the block islowered onto the vehicle and locked into place. The vehicle then moveson. The up and down distance for the block unload/load process is only afew inches. Other methods of unloading storage blocks are possible,including wheeled transfer carts. One promising alternative is the useof a rollway, in which the block would be pushed or pulled off a flatplane of rollers on top of the vehicle to a corresponding flat plane ofrollers on the lateral storage track.

FIG. 35 shows an illustrative layout for the mass storage yard, based ona 100 meter wide by 300 meter wide storage area. A typical storage masshas dimensions of about 3.5 meters in width, about 2.5 meters in height,and about 4.5 meters in length. With about 1.5 meters between adjacentmasses, along the width and length, a 7 acre yard could store 1000masses, equivalent to 500 MWH of electrical energy. Additional storagecould be easily supplied by increasing the width and/or length of theyard.

The storage masses would be laid out in rows of 20 (10 on each side ofthe guideway), with approximately 1 meter spacing between masses.

FIG. 36 shows an illustrative loading pattern for the storage masses. Assuccessive vehicles moved up to a given row, they would unload theirstorage masses and then move out to return to the base of a guideway topick up additional masses to be transported uphill. The unloaded masseswould alternately move right and left along the row, to be stored thereuntil they were needed for electrical generation, when they would bemoved back along the row to be loaded onto vehicles.

The pattern shown in FIG. 36 corresponds to the case where the unloadtime on a vehicle is shorter than the time internal between arrivingvehicles. If the unload time is longer than the interval betweenvehicles, more than one row would be engaged in unloading vehicles atthe same time. The vehicles would then move in coordinated blocks ofseveral rows, with the number of rows determined by the ratio of unloadtime to the time interval between arriving vehicles.

The load pattern for the system of the invention for electrical powerstorage and delivery would be similar to the unload pattern, except thatthe storage masses would move inward along the rows towards the guidewayrather than outward.

EXAMPLE System Parameters for Baseline Vehicle/Guideway Configuration

-   2 kilometer elevation change;-   100 ton storage mass;-   0.5 MWH stored per unit 100 ton mass;-   45 degree angle of inclination for guideway (nominal);-   Either above surface or below surface (tunnel) guideway;-   >90% energy storage efficiency (output/input);-   10 ton vehicle weight (unloaded);-   110 ton vehicle weight (loaded);-   60 meter/sec (134 mph) vehicle velocity;-   10 round trips per hour for vehicle;-   100 seconds to load or unload vehicle;-   Dipole loop magnets along each side of vehicle;-   1 meter magnet pitch (distance between loops having same polarity);-   10 magnet pairs per vehicle (5 on each side);-   0.5 meter loop width;-   Narrow beam guideway;-   Iron plates above vehicle dipole loops provide vehicle lift force;-   Figure of 8 null flux guideway loops provide vertical stability; and-   Dipole null flux guideway loops provide lateral stability.

A 60 hertz, three phase propulsion winding acts as motor to propelloaded vehicle up grade to store energy, and as generator when loadedvehicle goes down grade, to return electric power to grade.

One facility for the system of the invention for electrical powerstorage and delivery could deliver, if desired, 1000 MW(e), or more, ofoutput power; or 1000 MWH, or more, of stored electric energy.

The facility for the system of the invention for electrical powerstorage and delivery could come on line in less than one minute, and canbe used as spinning reserve.

The system of the invention for electrical power storage and deliveryhas minimum environmental impact: i.e., producing no pollution (gases,CO₂, or thermal); producing no significant noise; requiring a small landfoot print for an above surface facility (40 acres for 1000 MWH); andrequiring no land foot point for sub-surface facility.

The principal parameters for a baseline system utilizing an inclinedguideway are given in the example above. The values are illustrative andcould be somewhat different for an actual application, depending onterrain, required storage capacity, and the like However, it appearssimple to adjust the parameters to whatever conditions exist in theactual application.

The input/output voltage of the propulsion windings for the system ofthe invention for electrical power storage and delivery is determined bythe number of turns in the guideway propulsion loops. At 60 meters persecond and 7 inch separation, the 5 magnet pairs on each side of thevehicle will generate 500 volts rms in each phase of the three phasewindings, per turn of winding. Depending on the desired voltage levelfor the transformers that connect the system of the invention forelectrical power storage and delivery to the grid, the number of turnsin the propulsion winding will be determined. At 12 KV, for example, thepropulsion winding would require 12,000/500 or 24 turns, if the windingson the sides of the vehicle were connected in parallel, or 12 turns ifconnected in series.

The blocks can be rapidly moved onto or off from the vehicle using anoverhead trolley-wheel system as illustrated in FIGS. 33A and 33B, or onrollways, and can be stored on pads located adjacent to the maglevguideway at its high and low altitude points. A 100 meter×600 meter long(6 acres) storage facility could handle and deliver 2000 storage masses,equivalent to 1000 MWH of electrical energy at an elevation change of 2kilometers (6000 feet). Overall energy efficiency, output electricalenergy/input electrical energy, would be well above 90%—much higher thanany other electrical storage technology.

For a mass unload time of 100 seconds and a mass load time also of 100seconds (both steps are necessary during a vehicle round trip, whetherthe system of the invention for electrical power storage and delivery isoperating in the power storage or power delivery mode) a given vehiclefor the system of the invention for electrical power storage anddelivery could make 10 round trips per hour. This is quite conservative,since the 100 second intervals could probably be reduced to about 30seconds, considering the simplicity of the transfer process, and thefact that the block only has to be lifted by a few inches to enable thevehicle to move forward for the return half of its round trip. The totalnumber of round trips per hour would then approach 20.

The small land footprint and absence of environmental problems, togetherwith its low storage cost, make the system of the invention forelectrical power storage and delivery very attractive for peaking powerand spinning reserve applications. In the near term, buying excessbaseload night-time power at $50 per MWH (5 cents/KWH), storing it inthe system, and selling it at $200 per MWH for peaking power, a pricethat corresponds to typical peaking power cost in California, wouldyield a return on the total capital investment (ROD in the system of theinvention for electrical power storage and delivery of approximately 67percent per year, assuming that it delivered power for 1500 hoursannually. Such a rate of return would make the system of the inventionfor electrical power storage and delivery a very attractive investmentproposition. A 500 MW(e) unit delivering power for 4 hours daily wouldproduce net revenues (sales—cost of purchased power—O&M costs) of 100million dollars per year on a total capital investment of 150 milliondollars.

A second, very attractive feature is the completely non-pollutingenvironmentally benign nature of the system of the invention forelectrical power storage and delivery. This feature, and its ability tosubstitute for peaking plants that burn fossil fuels and producepollution, should make it possible to obtain permits and site approvalvery quickly and easily. Furthermore, since the maglev guideway wouldnot carry passengers, safety certification would be considerably easier.

Facilities for the system of the invention for electrical power storageand delivery could be erected in a short time, e.g., 3 years or less, tomeet increasing peak power demands. The total land use for a 2000 MWHfacility, including a dual 3 km long guideway, is only about 20 acres.Most facilities would be sited in remote areas and would not impact theenvironment. At the design speed of 130 mph, the vehicles would bevirtually silent, with aerodynamic noise below ambient levels.

The system of the invention for electrical power storage and delivery isvery attractive for near term peaking power needs. It is even moreattractive for low cost energy storage used in conjunction with solarand wind power generation. The electric output from solar and wind powersources is inherently variable and nonpredictable. Combined with thesystem of the invention for electrical power storage and delivery,however, solar and wind sources can deliver steady, reliable power thatmeets variations in load demand.

The cost of steady power from solar electrical generation in combinationwith the system of the invention for electrical power storage anddelivery is competitive with the cost of new combined cycle natural gaspower plants, and is expected to be increasingly competitive as demandfor oil and gas grows and reserves are depleted, and their cost rises.

Wind power capacity is increasing very rapidly in this country, and bythe end of the decade, it could easily reach 10% of US capacity,especially if there were a low cost energy storage system available toit. The present invention, when used in combination with wind powergeneration of electricity, allows even greater reliance to be placed onnormally unpredictable wind power, since power can be supplied to thegrid even when the wind was not blowing.

An attractive spin-off of the system of the invention for electricalpower storage and delivery is the demonstration of a practical maglevmining capability. The about 100 ton mass lifting capability of thesystem of the invention for electrical power storage and deliverysubstantially exceeds the lifting capability required for mining, whichis probably 20 to 30 tons at a maximum.

There are a number of different alternate embodiments that can store anddeliver electrical energy. As is illustrated in FIG. 37, storage anddelivery of stored electrical energy can be accomplished bysuperconducting maglev vehicles via (1) the narrow beam configurationfor inclined guideways, and its derivative configuration for verticalshaft guideways, and (2) a planar configuration for inclined guideways.Embodiments for the system of the invention for electrical power storageand delivery in which electromagnets or permanent magnets are used inconjunction with iron lift plates are also possible (FIG. 37). However,expensive fast response servo control of the magnetic lift force wouldbe required on each vehicle. In addition, the lift force issubstantially weaker than that with superconducting magnets, and thesuspension gap would be much smaller—e.g., a quarter of an inch comparedto about 6 inches with superconducting magnets. The much greaterprecision required for such smaller gap suspensions would greatlyincrease guideway cost relative to that for superconducting maglev.

Systems according to the invention for electrical power storage anddelivery can also be designed to use steel wheel on rail suspensions forthe vehicle, with electromagnetic propulsion, as indicated in FIG. 37.The method of propulsion can use either superconducting magnetspermanent or electromagnets on the vehicle.

The use of steel wheel on rail suspensions for an energy storagevehicle, while technically feasible appears to have significantlimitations:

-   -   1) Operating speed of 60 mph (134 mph) would be hard to achieve.    -   2) The vehicles would need elaborate, heavy secondary        suspensions.    -   3) The rails and wheels would require frequent maintenance and        repair, due to the heavy usage.

FIGS. 38 and 39 show two alternate designs to the baseline design forthe narrow beam guideway. The design in FIG. 38 provides for an attachedsupport structure 156 for (1-1) and (3-3) guideway dipole loops 158. Thedesign in FIG. 39 uses the iron lift plates positioned to providelateral stability instead of null flux dipole loops. If the vehiclemoves either left or right laterally due to an external force, the ironplates generate an equal and opposite force to move the vehicle back toits equilibrium lateral position.

The iron plate suspension is not stable vertically, however. Theinductive loops at the bottom of the narrow beam provide verticalstability, instead of the null flux Figure of 8 loops. If the verticalmoves upwards or downwards due to an external force, the combination oflift forces from the iron lift plates, together with the lift forcesfrom the inductive loops is stabilizing. That is, if the vehicle ispushed upwards, the lift force becomes smaller than the vehicle weight,causing it to return to its equilibrium position. If the vehicle ispushed downwards, the lift force becomes greater than the vehicleweight, causing it to return to its equilibrium position.

FIG. 39 shows a variant on the FIG. 38 design, in which the guidewayinductive loops are replaced by conducting sheets 160, such as aluminumsheets, for example. It will behave like the inductive loop design,except that the I²R losses are greater with the conducting sheet design.

FIG. 40 shows a configuration for a planar guideway 162 for the systemof the invention for electrical power storage and delivery while FIG. 41shows a narrow beam configuration using superconducting quadrupolemagnets on the vehicle instead of dipole. The quadrupole design wouldenable the vehicle to travel on, and transition between, both the narrowbeam and planar guideways.

The technology for the system of the invention for electrical powerstorage and delivery can be used for other applications besides energystorage. One promising application is the upwards transport of mine oresfrom underground and open pit mines. In general, open pit mines woulduse angled surface guideways, while underground mines could use eitherangled underground tunnels or vertical shafts. In contrast to the systemof the invention for electrical power storage and delivery, maglevmining systems would only transport the heavy masses upwards, and notupwards during electrical storage periods and downwards duringelectrical delivery periods.

A second difference between the system of the invention for electricalpower storage and delivery and maglev mining is that the magnitude ofthe masses carried will be considerably smaller, e.g., 20 to 30 tons formining compared to 100 tons for the system of the invention forelectrical power storage and delivery. This greatly reduces the I²Rlosses in the propulsion windings, as well as the electric power neededto push the vehicles upwards.

EXAMPLE Principal Parameters for Baseline maglev Mining System UsingAngled Guideways

-   500 meter elevation change;-   25 ton ore mass;-   45 degree angle of inclination;-   Either open pit surface or underground mine;-   >90% electrical storage efficiency;-   10 ton vehicle weight (unloaded);-   35 ton gross vehicle (loaded);-   30 meter/sec (67 mph) vehicle velocity;-   60 seconds to load or unload vehicle;-   20 round trips per hour for vehicles;-   500 tons per hour capacity per vehicle;-   Dipole loop magnets along each side of vehicle;-   1 meter magnet pitch (distance between loops having same polarity);-   30 hertz frequency in propulsion winding;-   10 magnet pairs per vehicle (5 on each side);-   Narrow beam guideway;-   Iron plates above vehicle dipole loops provide vehicle lift force;-   Figure of 8 null flux guideway loops provide vertical stability;-   Dipole null flux guideway loops provide lateral stability; and-   A 30 hertz propulsion winding acts as motor to propel loaded vehicle    up the guideway.

The example above gives the principal parameters for a baseline maglevmining system using energy storage vehicles according to the system ofthe invention for electrical power storage and delivery on an inclinedguideway. The example below give the principal parameters for a baselinemaglev mining system using energy storage vehicles according to thesystem of the invention for electrical power storage and delivery on avertical shaft guideway.

EXAMPLE Principal Parameters for Baseline maglev Mining System UsingVertical Shaft Guideway

2000 meter elevation change;

-   25 ton ore mass;-   90 degree angle of elevation;-   Below surface;-   10 ton vehicle weight (unloaded);-   35 ton vehicle weight (loaded);-   30 meters/sec (67 mph);-   10 round trips per hour for vehicle;-   100 seconds to load or unload vehicle;-   Dipole loop magnets along each side of vehicle;-   1 meter magnet pitch (distance between loops of same polarity);-   10 magnet pairs per vehicle (5 on each side);-   0.5 meter loop width; and-   A 30 hertz propulsion winding acts as motor to propel loaded vehicle    up the shaft.

It will be apparent from the foregoing that while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the invention belimited, except as by the appended claims.

1. A method for generation of electrical energy, comprising the steps of: a) providing at least one magnetic levitation vehicle; b) providing a vertically oriented magnetic levitation guideway for the at least one magnetic levitation vehicle, the magnetic levitation guideway extending between an elevated upper end and a lower end at a lower elevation, the magnetic levitation guideway having a plurality of magnetic propulsion windings for propulsion of the at least one magnetic levitation vehicle; c) loading a storage mass on the at least one magnetic levitation vehicle; d) moving the at least one magnetic levitation vehicle from the elevated upper end of the magnetic levitation guideway to the lower end of the magnetic levitation guideway to generate electrical energy through the propulsion windings of the magnetic levitation guideway; e) powering said magnetic propulsion windings by electricity from a regional electrical power grid; and f) delivering said electrical energy generated through said propulsion windings to said regional electrical power grid.
 2. The method of claim 1, further comprising the step of unloading the storage mass from the at least one magnetic levitation vehicle at the lower end of the magnetic levitation guideway.
 3. The method of claim 2, further comprising the step of moving the unloaded at least one magnetic levitation vehicle from the lower end of the magnetic levitation guideway to the upper end of the magnetic levitation guideway.
 4. The method of claim 3, further comprising repeating steps c) and d).
 5. The method of claim 1, wherein at least a portion of said magnetic levitation guideway is disposed in a sub-surface tunnel.
 6. A method for generation of electrical energy, comprising the steps of: providing at least one magnetic levitation vehicle; providing a vertically oriented magnetic levitation guideway for the at least one magnetic levitation vehicle, the magnetic levitation guideway extending between an elevated upper end and a lower end at a lower elevation, the magnetic levitation guideway having a plurality of magnetic propulsion windings for propulsion of the at least one magnetic levitation vehicle; loading at least one storage mass on the at least one magnetic levitation vehicle at the lower end of the magnetic levitation guideway; propelling the at least one magnetic levitation vehicle with the at least one storage mass from the lower end of the magnetic levitation guideway to the upper end of the magnetic levitation guideway; unloading the at least one storage mass from the at least one magnetic levitation vehicle at the upper end of the magnetic levitation guideway to store gravitational potential energy; powering said magnetic propulsion windings by electricity from a regional electrical power grid; and delivering electrical energy generated through said propulsion windings to said regional electrical power grid.
 7. The method of claim 6, further comprising the step of moving the at least one magnetic levitation vehicle from the elevated upper end of the magnetic levitation guideway to the lower end of the magnetic levitation guideway to convert the gravitational potential energy to electrical power through the propulsion windings of the magnetic levitation guideway.
 8. The method of claim 6, wherein at least a portion of said magnetic levitation guideway is disposed in a sub-surface tunnel.
 9. A system for generation of electrical energy, comprising: at least one magnetic levitation vehicle to transport a storage mass; a vertically oriented magnetic levitation guideway for the at least one magnetic levitation vehicle, the magnetic levitation guideway extending between an elevated upper end and a lower end at a lower elevation, the magnetic levitation guideway having a plurality of magnetic propulsion windings for propulsion of the at least one magnetic levitation vehicle; means for moving the at least one magnetic levitation vehicle from the elevated upper end of the magnetic levitation guideway to the lower end of the magnetic levitation guideway to generate electrical energy through the propulsion windings of the magnetic levitation guideway; means for delivering electrical power from a regional electrical power grid to power the propulsion windings; and means for delivering the electrical energy generated through the propulsion windings to the regional electrical power grid.
 10. The system of claim 9, wherein at least a portion of said magnetic levitation guideway is disposed in a sub-surface tunnel.
 11. A system for generation of electrical energy, comprising the steps of: at least one magnetic levitation vehicle; a vertically oriented magnetic levitation guideway for the at least one magnetic levitation vehicle, the magnetic levitation guideway extending between an elevated upper end and a lower end at a lower elevation, the magnetic levitation guideway having a plurality of magnetic propulsion windings for propulsion of the at least one magnetic levitation vehicle; means for loading at least one storage mass on the at least one magnetic levitation vehicle at the lower end of the magnetic levitation guideway; said magnetic propulsion windings provided for propelling the at least one magnetic levitation vehicle with the at least one storage mass from the lower end of the magnetic levitation guideway to the upper end of the magnetic levitation guideway; means for unloading the at least one storage mass from the at least one magnetic levitation vehicle at the upper end of the magnetic levitation guideway to store gravitational potential energy; means for moving the at least one magnetic levitation vehicle from the elevated upper end of the magnetic levitation guideway to the lower end of the magnetic levitation guideway to convert the gravitational potential energy to electrical power though the propulsion windings of the magnetic levitation guideway; means for delivering electrical power from a regional electrical power grid to power the propulsion windings; and means for delivering the electrical power converted through the propulsion windings to the regional electrical power grid.
 12. The system of claim 11, wherein at least a portion of said magnetic levitation guideway is disposed in a sub-surface tunnel. 